How many ODU3s are in an OTU4?

Working

OTU4 → 1 × ODU4 → 2 × ODU3

1. 1 × ODU4 in each OTU4 ITU-T G.709The OTU4 frame carries exactly one ODU4.
2. 2 × ODU3 in each ODU4 ITU-T G.709Each ODU3 takes 31 of the 80 ODU4 tributary slots, so 2 fit and 18 slots stay unused.

• 1 ODU4
• 1 × 2 = 2 ODU3s

Leftover capacity

31.171535602 Gbit/s of each OTU4 line rate (111.809973568 Gbit/s) sits outside 2 × 40.319218983 Gbit/s of ODU3 line rate (80.638437966 Gbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.

OTU4 reference · ODU3 reference · Open in the converter